AMD releases the first patch of its next-generation EPYC Zen 4 CPUs for Linux bringing in new capabilities

The first enabling patches for AMD's next-generation EPYC Zen 4 CPUs and the new capabilities built into them for Linux are now available. While AMD is still working on Zen…

By Nivedita Bangari

December 11, 2021

3 min read

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The first enabling patches for AMD’s next-generation EPYC Zen 4 CPUs and the new capabilities built into them for Linux are now available. While AMD is still working on Zen 3 on both client and server platforms, the Linux team at AMD is already releasing the first fixes for Zen 4 support. The latest upgrades feature compatibility for AMD’s next-generation EPYC server CPUs, which will handle 12-channel memory, according to Phoronix.

AMD has previously released fixes that enable compatibility for AMD EPYC CPUs with up to 12 CCDs, so both Genoa and Bergamo are now supported by Linux. For Zen 4 CPUs, there’s also new temperature monitoring support, and the current patch adds on the memory front.

Support for up to 12-channel RAM in both RDDR5 and LDDR5 versions is now included in the new patch. The AMD EPYC Zen 4 platforms will support both RDDR5 (Registered DDR5) and LRDDR5 (Load-Reduced DDR5) memory, with LRDDR5 geared at dense memory servers. Each CPU will have up to 12 memory controllers (per socket), compared to the current 8 memory controllers per chip. According to reports, AMD’s Zen 4 processors will be labelled as “Family 19h Models 10h-1Fh and A0h-AFC.”

The EPYC Genoa chip renders revealed a total of 12 CCDs (16 cores per CCD) to reach 96 cores, while the AMD Bergamo renders also show 12 CCDs, but either Zen 4C likely has more cores per CCD or the render shown wasn’t final, as a 16 core CCD configuration would require a total of 16 Zen 4 CCDs to reach 128 cores. The final die arrangement will undoubtedly be a sight to behold.

AMD EPYC CPU Families:

Family Name	AMD EPYC Naples	AMD EPYC Rome	AMD EPYC Milan	AMD EPYC Milan-X	AMD EPYC Genoa	AMD EPYC Bergamo	AMD EPYC Turin
Family Branding	EPYC 7001	EPYC 7002	EPYC 7003	EPYC 7003X?	EPYC 7004?	EPYC 7005?	EPYC 7006?
Family Launch	2017	2019	2021	2022	2022	2023-2024?	2024-2025?
CPU Architecture	Zen 1	Zen 2	Zen 3	Zen 3	Zen 4	Zen 4	Zen 5
Process Node	14nm GloFo	7nm TSMC	7nm TSMC	7nm TSMC	5nm TSMC	5nm TSMC	3nm TSMC?
Platform Name	SP3	SP3	SP3	SP3	SP5	SP5	SP5
Socket	LGA 4094	LGA 4094	LGA 4094	LGA 4094	LGA 6096	LGA 6096	LGA 6096
Max Core Count	32	64	64	64	96	128	256
Max Thread Count	64	128	128	128	192	256	512
Max L3 Cache	64 MB	256 MB	256 MB	768 MB?	384 MB?	TBD	TBD
Chiplet Design	4 CCD’s (2 CCX’s per CCD)	8 CCD’s (2 CCX’s per CCD) + 1 IOD	8 CCD’s (1 CCX per CCD) + 1 IOD	8 CCD’s with 3D V-Cache (1 CCX per CCD) + 1 IOD	12 CCD’s (1 CCX per CCD) + 1 IOD	12 CCD’s (1 CCX per CCD) + 1 IOD	TBD
Memory Support	DDR4-2666	DDR4-3200	DDR4-3200	DDR4-3200	DDR5-5200	DDR5-5600?	DDR5-6000?
Memory Channels	8 Channel	8 Channel	8 Channel	8 Channel	12 Channel	12 Channel	TBD
PCIe Gen Support	64 Gen 3	128 Gen 4	128 Gen 4	128 Gen 4	128 Gen 5	TBD	TBD
TDP Range	200W	280W	280W	280W	320W (cTDP 400W)	320W (cTDP 400W)	480W (cTDP 600W)